Hydrofoil

ABSTRACT

A hydrofoil for a watercraft has at least one wing and one connecting rod for attaching the at least one wing to a mast. A conically tapered projection is provided on the connecting rod and a conical recess is provided on the wing which engage in one another. The wedge angle of the conical recess is greater than the wedge angle of the conically tapered projection in order to allow angular adjustment between the connecting rod and the wing. By means of a fixing device, the connecting rod can be braced against a portion of the conical recess and/or the wing can be braced against a portion of the conically tapered projection.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC § 119 to German Patent Application No. DE 10 2018 124 323.5, filed on Oct. 2, 2018, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a hydrofoil for a watercraft, the hydrofoil comprising at least one wing and one connecting rod for attaching the at least one wing to a mast.

BACKGROUND

Hydrofoils make it possible to lift a board out of the water while traveling, for example during kitesurfing or jet skiing, in order to reduce the flow resistance. Propulsion can also be achieved by means of a hydraulic device that is attached to the drive device. The hydrofoil usually has a mast and at least one wing that is arranged thereon. The at least one wing is attached to the mast by means of a connecting rod. The mast, in turn, is attached to the board. During operation, only a portion of the mast and the wing(s) remain submerged in the water, while the board hovers above the water surface. One example of such a hydrofoil board is known from EP 2 907 737 B2.

It is an object of the invention to specify alternatives for connecting the at least one wing to the connecting rod. In particular, it is the object of the invention to improve the adjustability of the wing(s) in order to enable the ride characteristics of the hydrofoil to be more easily adapted to different needs.

SUMMARY

This object is achieved by a hydrofoil according to the claims. The hydrofoil comprises at least one wing and one connecting rod for attaching the at least one wing to a mast and is characterized in that a conically tapered projection is provided on the connecting rod and a conical recess is provided on the wing which engage in one another, the wedge angle of the conical recess being greater than the wedge angle of the conically tapered projection in order to allow angular adjustment between the connecting rod and the wing, and in that a fixing device is provided by means of which the connecting rod can be braced against a portion of the conical recess and/or the wing can be braced against a portion of the conically tapered projection.

The described connection between the connecting rod and the wing allows for stepless angular adjustment between the connecting rod and the wing over the range of the wedge angle difference between the conically tapered projection and the conical recess. The fixing device enables the desired angle to be set and maintained as required. As a result, the hydrofoil can be adjusted depending on the preference of the driver, the water temperature, salt or fresh water, the wave pattern, and the like, so that optimum performance and/or ride comfort is achieved, for example.

Advantageous embodiments of the invention constitute the subject matter of additional claims.

In one design variant, the fixing device can have a threaded opening transverse to the projection and a threaded bolt that is screwed into the threaded opening for the purpose of adjusting the angle. The desired angle can be easily adjusted by twisting the threaded bolt.

Preferably, the threaded opening is formed on the conically tapered projection of the connecting rod, whereas the threaded bolt that is screwed therein can be braced against a conical inner wall portion of the conical recess for angular adjustment. As a result, the fixing device can be accommodated virtually completely inside the hydrofoil without impairing the incidence of flow against same.

According to another embodiment, at least two pairs of a threaded opening and a threaded bolt, respectively, are provided, it being possible to brace one of the threaded bolts against a conical inner wall portion of the conical recess on the wing and to brace the other threaded bolt of such a pair against an inner wall portion that is situated opposite the first-mentioned conical inner wall portion of the conical recess of the wing. This enables the angular position of the wing relative to the connecting rod to be fixed in an especially simple manner. In addition, this design variant is especially streamlined, since no portions of the fixing device protrude outward.

Furthermore, the connecting rod and the wing can be supported and braced against one another by means of mutually facing axial support surfaces in order to ensure a backlash-free connection of the wing to the connecting rod.

For axial fixation, a tension anchor can be inserted transverse to the longitudinal direction of the connecting rod into a connecting portion of the wing, whereas a tension bolt that is supported on the connecting rod is screwed into the tension anchor. A secure connection between the two components is accomplished in a simple manner by tightening the tension bolt.

According to another design variant, the tension anchors extends transverse to the longitudinal direction of the connecting rod through the wing, particularly through the conical recess of the wing, whereby an especially stable backlash-free connection of the wing to the connecting rod is achieved.

The conical recess of the wing can be formed on rod-shaped connecting portion of the wing. This rod-shaped connecting portion can be formed integrally with the wing. By integrating a portion of the connection between the wing and the mast into the wing, the hydrofoil according to the invention can be folded together in an especially compact manner when in the disassembled state.

Furthermore, the conically tapered projection of the connecting rod can have a non-circular cross-sectional profile, particularly a rectangular, square, or oval-shaped cross-sectional profile. Good lateral guidance of the wing is thus achieved on the connecting rod, whereas the adjustment mechanism described above enables an angular adjustment of the wing to be achieved through swiveling up and down in the installed position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in further detail below with reference to an exemplary embodiment that is illustrated in the drawing. Description of the drawings:

FIG. 1 shows a perspective view of a hydrofoil according to an embodiment of the invention that is attached to a board indicated by broken lines,

FIG. 2 shows a vertical section of the connecting portion between the connecting rod and a wing of the hydrofoil in a schematic, not-to-scale representation, and

FIG. 3 shows a horizontal section of the connecting portion between the connecting rod and a wing of the hydrofoil.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The exemplary embodiment illustrated in FIGS. 1 to 3 shows a hydrofoil 1 for a watercraft. For explanatory purposes, FIG. 1 shows an example of a watercraft as a board 2 that is suitable for kitesurfing or jet skiing and to which a hydraulic hose 1 is attached. However, it is also possible to use corresponding hydrofoils 1 on boats, for example.

The hydrofoil 1 has a mast 3, a connecting rod 4, a front wing 5, and a rear wing 6. These components are embodied as separate components and connected to one another in such a way that they can be replaced individually. This makes it possible to flexibly adapt the hydrofoil 1 to different purposes. The hydrofoil 1 can be folded together very compactly in order to be transported. Optionally, it is also possible to integrate two or more of these components into a one-piece component.

The mast 3 has a first end portion 7 for attachment to the board 2 and a second end portion 8 for connecting the connecting rod 4. In the vertical direction z, the mast 3 has a height in the range of preferably from 700 to 1200 mm; in the longitudinal direction or direction of forward travel x, the mast 3 has a length in the range of preferably from 80 to 150 mm; and in the transverse direction y, the mast 3 has a thickness in the range of preferably from 10 to 30 mm.

The mast 3 is preferably made of a fiber composite plastic such as carbon fiber-reinforced plastic (CFRP) or glass fiber-reinforced plastic (GRP). It can also be made of an aluminum alloy or a layered composite material.

The first end portion 7 of the mast 3 can form a flange-like attachment portion 9 that is widened relative to its remaining cross section and provides a bearing surface for the underside of the board 2.

The second end portion 8 has a receptacle for the connecting rod 4 at the free end of the mast 3. The receptacle can be instantiated in the form of a through hole in which the connecting rod 4 is held. Instead of a through hole, the receptacle can also be embodied as a recess, particularly a groove, that is open on one longitudinal side and in which the connecting rod 4 is fixed.

The front wing 5 and the rear wing 6 in the direction of forward travel are attached to the mast 3. Forces occurring on the wings 5 and 6 during operation are supported against the mast 3 by means of the connecting rod 4. The connecting rod 4 is thus secured against rotation about its longitudinal axis on the mast 3. This can be achieved, for example, through appropriate profiling of the connecting rod 4 and of the receptacle on the mast 3 and/or with the aid of suitable attachment means as explained in greater detail in EP 2 907 737 A1.

The connecting rod 4 is made of metal, preferably a steel, titanium, or aluminum alloy. It has a width and height in the range of preferably from 10 to 30 mm, which keeps the flow resistance in the water low. The length of the connecting rod 4 is preferably in the range from 400 to 1000 mm.

The front wing 5 and the rear wing 6 are arranged one behind the other in the direction of travel and attached to a front and rear end portion 10, 11 of the connecting rod 4. In particular, the front wing 5 is seated on the front end portion 10 and the rear wing 6 on the rear end portion 11 of the connecting rod 4, so that the front wing 5 is located in front of the mast 3 and the rear wing 6 behind the mast 3 relative to the direction of forward travel x. The rear wing 6 and optionally also the front wing 5 can be spaced apart from the mast 3.

The attachment of the connecting rod 4 to the mast 3 can be preferably released. In addition, at least one of the wings 5 and 6 is releasably attached to the connecting rod 4. As a result, connecting rods 4 of different lengths can be attached to the mast 3 in order to change the position of the wings 5 and 6. Furthermore, different front and rear wings 5 and 6 can be attached to the connecting rod 4.

The wings 5 and 6 are preferably made of fiber composite plastic, particularly carbon fiber-reinforced plastic (CFRP) or glass fiber-reinforced plastic (GRP), or of a layered composite material.

The attachment of a wing to the connecting rod 4 is shown in more detail in FIGS. 2 and 3.

A conically tapered projection 12 that extends in the longitudinal direction of the connecting rod 4 is formed for this purpose on the connecting rod 4, particularly on an axial end portion thereof. This conically tapered projection 12 engages in a conical recess 13 on the wing 5 or 6.

The conical recess 13 can be arranged directly in the vicinity of the wing surfaces 14 of the wing 6. In the exemplary embodiment that is illustrated, however, the wing 6 has a rod-shaped connecting portion 15 that couples the actual wing surfaces 14 with the connecting rod 4. The rod-shaped connecting portion 15 can be formed integrally with the wing surfaces 14.

As can be seen from FIG. 2, the conical recess 13 has a larger wedge angle a2 than the conically tapered projection 12 (a1). This makes it possible to adjust the angle between the connecting rod 4 and the wing 6 in the vertical direction. The adjustment range is preferably no more than +/−2° and more preferably no more than +/−1.5°.

In the assembled state, the conically tapered projection 12 is fully inserted axially into the conical recess 13, so that the connecting rod 4 and the wing 6 are mutually supported by mutually facing axial support surfaces 16 and 17.

The outer wedge surfaces 18 on the projection 12 and the conical inner wall surfaces 19 of the conical recess 13 converge in the vicinity of the axial support surfaces 16 and 17, so that a joint for the vertical angle adjustment is formed at this point and the connection between the connecting rod 4 and the wing 6 to the axial support surfaces 16 and 17 is free of backlash. This ensures a continuous transition of the outer contour of the connecting rod 4 into the connecting portion 15 of the wing 6.

In the transverse direction of the connecting rod 4—i.e., transverse to the longitudinal axis A and transverse to the vertical direction in the installed position—the conically tapered projection 12 and the conical recess 13 are guided against one another, as can be seen in FIG. 3, so that no angular displacement between the wing 6 and the connecting rod 4 is possible in the transverse direction. This can be achieved, for example, by providing the conically tapered projection 12 of the connecting rod 4 with a non-circular cross-sectional profile. For example, the cross-sectional profile can be rectangular, square, or oval.

Furthermore, a fixing device 20 is provided in the connecting region by means of which the connecting rod 4 can be braced against a portion of the conical recess 13 and/or the wing 5, 6 can be braced against a portion of the conically tapered projection 12. The desired angular position between the connecting rod 4 and the wing 5, 6 is thus established and/or the joint between the connecting rod 4 and the wing is fixed.

In the exemplary embodiment that is shown, the fixing device 20 has a threaded opening 21 transverse to the projection 12 and a threaded bolt 22 that is screwed into the threaded opening 21. In principle, the threaded opening 21 can be formed both in the projection 12 and in the wall region surrounding the conical recess 13. Since the latter is preferably made of a fiber composite material, the threaded opening 21 will be preferably formed in the projection 12. Depending on the position of the threaded opening 21, the threaded bolt 22 is braced against the conical inner wall surface 19 of the recess 13 or against the wedge surface 18 of the projection 12 in order to set a desired angular position between the connecting rod 4 and the wing.

The fixing device 20 not only enables the angular position to be determined but also offers the possibility of easily adjusting the pitch of the wing 5 or 6 at the connecting rod 4 through appropriate adjustment of the threaded bolt 22.

Preferably, at least two pairs of a threaded opening 21 and a threaded bolt 22, respectively, are provided as a fixing device 20 in the connecting region and arranged in opposite directions relative to one another. The desired pitch can be set by means of the first threaded bolt 22 and fixed by means of the second threaded bolt 22.

As FIG. 2 shows, in the present exemplary embodiment, one of the threaded bolts 22 can be braced against a first conical inner wall portion 19 of the conical recess 13 on the wing 5 or 6, whereas the other threaded bolt 22 of such a pair can be braced against a second conical inner wall portion 19 of the conical recess 13 of the wing 5 or 6 that is situated opposite the first-mentioned conical inner wall portion 19.

Appropriate through holes 23 are embodied in the outer wall surrounding the conical recess 13 in order to enable a tool to reach the threaded bolts 22.

In principle, the wing 5 or 6 can be secured axially on the connecting rod 4 in any desired manner. In the present exemplary embodiment, a tension anchor 24 that is inserted transverse to the longitudinal direction A of the connecting rod 4 into a connecting portion 15 of the wing 5 or 6 is used for this purpose. A tension bolt 25 that is supported on the connecting rod 4 is screwed into this tension anchor 24. As a result of the tension bolt 25 being screwed into the tension anchor, the wing 5 or 6 is pulled in the direction of the connecting rod 4 in order to brace the axial support surfaces 16 and 17 against one another.

The tension anchor 24, which can be embodied as a transverse bolt, for example, extends transverse to the longitudinal direction of the connecting rod 4 through the wing 5 or 6, particularly through the conical recess 13 thereof. A through hole 26 in the form of a slotted hole or the like can be provided for this purpose on the projection 12 of the connecting rod 4.

The above-described connection between the connecting rod 4 and the wing 5 or 6 allows for stepless angular adjustment in the vertical direction z. The desired angle can be adjusted and maintained as required by means of the fixing device 20. Since the fixing device 20 is housed completely within the hydrofoil, the flow behavior of the latter remains unimpaired. Nevertheless, a very stable, backlash-free connection between the connecting rod 4 and the wing 5 or 6 is achieved.

The invention has been explained in more detail above with reference to an exemplary embodiment and additional variants. The exemplary embodiment and the other variants serve the purpose of demonstrating the practicability of the invention. Individual technical features that have been explained above in the context of additional individual features can also be implemented independently of these and in combination with other individual features, even if this is not expressly described, as long as this is technically possible. In particular, features of the variants can be adopted individually or in combination in a hydrofoil according to the exemplary embodiment. The invention is therefore expressly not limited to the specific exemplary embodiment described and the variants shown, but rather includes any and all embodiments defined by the claims.

LIST OF REFERENCE NUMERALS

-   1 hydrofoil -   2 board -   3 mast -   4 connecting rod -   5 front wing -   6 rear wing -   7 first end portion -   8 attachment portion -   9 second end portion -   10 front end portion -   11 rear end portion -   12 conically tapered projection -   13 conical recess -   14 wing surfaces -   15 connecting portion -   16 axial support surface of the connecting rod -   17 axial support surface of the wing -   18 wedge surface of the projection -   19 conical inner wall portion -   20 fixing device -   21 threaded opening -   22 threaded bolt -   23 opening -   24 tension anchor -   25 tension bolt -   26 through hole -   x longitudinal direction (direction of forward travel) -   y transverse direction -   z vertical direction -   A longitudinal axis -   α₁ wedge angle of the projection 12 -   α₂ wedge angle of the recess 13 

What is claimed is:
 1. A hydrofoil (1), comprising at least one wing (5, 6) and one connecting rod (4) for attaching the at least one wing (5, 6) to a mast, wherein a conically tapered projection (12) is provided on the connecting rod (4) and a conical recess (13) is provided on the wing (5, 6) that engage in one another, the wedge angle (α₂) of the conical recess (13) being greater than the wedge angle (α₁) of the conically tapered projection (12) in order to allow angular adjustment between the connecting rod (4) and the wing (5, 6), and that a fixing device (20) is provided by means of which the connecting rod (4) can be braced against a portion of the conical recess (13) and/or the wing (5, 6) can be braced against a portion of the conically tapered projection (12).
 2. The hydrofoil of claim 1, wherein the fixing device (20) has a threaded opening (21) transverse to the projection (12) and a threaded bolt (22) that is screwed into the threaded opening (21) for the purpose of adjusting the angle.
 3. The hydrofoil of claim 2, wherein the threaded opening (21) is formed on the projection (12), and the threaded bolt (22) that is screwed into same can be braced against a conical inner wall portion (19) of the conical recess (13) for the purpose of adjusting the angle.
 4. The hydrofoil of claim 2, wherein at least two pairs of a threaded opening (21) and a threaded bolt (22), respectively, are provided, it being possible to brace one of the threaded bolts (22) against a conical inner wall portion (19) of the conical recess (13) on the wing (5, 6) and to brace the other threaded bolt (22) of such a pair against an inner wall portion (19) that is situated (19) opposite the first-mentioned conical inner wall portion (19) of the conical recess (13) of the wing (5, 6).
 5. The hydrofoil of claim 3, wherein at least two pairs of a threaded opening (21) and a threaded bolt (22), respectively, are provided, it being possible to brace one of the threaded bolts (22) against a conical inner wall portion (19) of the conical recess (13) on the wing (5, 6) and to brace the other threaded bolt (22) of such a pair against an inner wall portion (19) that is situated (19) opposite the first-mentioned conical inner wall portion (19) of the conical recess (13) of the wing (5, 6).
 6. The hydrofoil of claim 1, wherein the connecting rod (4) and the wing (5, 6) are supported and braced against one another by means of mutually facing axial support surfaces (16, 17).
 7. The hydrofoil of claim 6, wherein a tension anchor (24) is inserted transverse to the longitudinal direction of the connecting rod (4) into a connection portion (15) of the wing (5, 6), and a tension bolt (25) that is supported on the connecting rod (4) is screwed into the tension anchor (24).
 8. The hydrofoil of claim 7, wherein the tension anchor (24) extends transverse to the longitudinal direction of the connecting rod (4) through the wing (5, 6).
 9. The hydrofoil of claim 7, wherein the tension anchor (24) extends through the conical recess (13) of the wing (5, 6).
 10. The hydrofoil of claim 4, wherein the connecting rod (4) and the wing (5, 6) are supported and braced against one another by means of mutually facing axial support surfaces (16, 17).
 11. The hydrofoil of claim 10, wherein a tension anchor (24) is inserted transverse to the longitudinal direction of the connecting rod (4) into a connection portion (15) of the wing (5, 6), and a tension bolt (25) that is supported on the connecting rod (4) is screwed into the tension anchor (24).
 12. The hydrofoil of claim 11, wherein the tension anchor (24) extends transverse to the longitudinal direction of the connecting rod (4) through the wing (5, 6).
 13. The hydrofoil of claim 12, wherein the tension anchor (24) extends through the conical recess (13) of the wing (5, 6).
 14. The hydrofoil of claim 1, wherein the conical recess (13) of the wing (5, 6) is formed on a rod-shaped connecting portion (15) of the wing (5, 6).
 15. The hydrofoil of claim 1, wherein the conically tapered projection (12) of the connecting rod (4) has a non-circular cross-sectional profile.
 16. A board (2) with a hydrofoil (1), the hydrofoil (1) comprising at least one wing (5, 6) and one connecting rod (4) for attaching the at least one wing (5, 6) to a mast, wherein a conically tapered projection (12) is provided on the connecting rod (4) and a conical recess (13) is provided on the wing (5, 6) that engage in one another, wherein a wedge angle (α₂) of the conical recess (13) is greater than a wedge angle (α₁) of the conically tapered projection (12) in order to allow angular adjustment between the connecting rod (4) and the wing (5, 6), and wherein a fixing device (20) is provided by means of which the connecting rod (4) can be braced against a portion of the conical recess (13) and/or the wing (5, 6) can be braced against a portion of the conically tapered projection (12). 